On Tue, Aug 27, 2019 at 03:55:23PM +0200, Ulf Hansson wrote: > On Tue, 27 Aug 2019 at 15:43, Russell King - ARM Linux admin > <linux@xxxxxxxxxxxxxxx> wrote: > > > > Hi, > > > > While dd'ing the contents of a SD card, I get hung task timeout > > messages as per below. However, the dd is making progress. Any > > ideas? > > > > Presumably, mmc_rescan doesn't get a look-in while IO is progressing > > for the card? > > Is it a regression? > > There not much of recent mmc core and mmc block changes, that I can > think of at this point. No idea - I just repaired the SD socket after the D2 line became disconnected, and decided to run that command as a test. > > ARM64 host, Macchiatobin, uSD card. > > What mmc host driver is it? mmci? sdhci-xenon. I'm just trying with one CPU online, then I'll try with two. My suspicion is that there's a problem in the ARM64 arch code where unlocking a mutex doesn't get noticed on other CPUs. Hmm, I thought I'd try bringing another CPU online, but it seems like the ARM64 CPU hotplug code is broken: [ 3552.029689] CPU1: shutdown [ 3552.031099] psci: CPU1 killed. [ 3949.835212] CPU1: failed to come online [ 3949.837753] CPU1: failed in unknown state : 0x0 which means I can only take CPUs down, I can't bring them back online without rebooting. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up According to speedtest.net: 11.9Mbps down 500kbps up
